US3709969A

US3709969A - Method for continuously extruding net-like structures composed of twisted multifilament yarns

Info

Publication number: US3709969A
Application number: US00104033A
Authority: US
Inventors: T Fairbanks
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1971-01-05
Filing date: 1971-01-05
Publication date: 1973-01-09
Anticipated expiration: 1990-01-09

Abstract

METHOD OF MAKING NET-LIKE STRUCTURES IN WHICH PAIRED GROUPS OF EXTRUDED FILAMENTS ARE PERIODICALLY SHIFTED TO PROVIDE DIFFERNT PAIRS, WHILE THE FILAMENTS IN EACH SUCH GROUP ARE TWISTED INTO A YARN. ALTERNATELY WITH SUCH SHIFTING, THE PAIRED GROUPS OF FILAMENTS AR ROTATED A MULTIPLE OF 180* ABOUT AND AXIS BETWEEN THE GROUP OF EACH SUCH PAIR.

D R A W I N G

Description

United States Patent U.S. Cl. 264-103 5 Claims ABSTRACT F THE DISCLOSURE Method of making net-like structures in which paired groups of extruded filaments are periodically shifted to provide different pairs, while the filaments in each such group are twisted into a yarn. Alternately with such shifting, the paired groups of filaments are rotated a multiple of 180 about an axis between the group of each such pair.

This application is a continuation-inpart of my application Ser. No. 825,213, filed on May 16, 1969, now U.S. Pat. 3,613,161.

The present invention is directed to a method for making net-like structures of twisted multitilament yarns.

In U.S. Pat. No. 3,331,903 there is disclosed a method and apparatus for making a net from plastic material by extruding a plurality of pairs of monofilaments of plastic material in such a manner that the filaments in each pair are spaced from each other in a first direction and the pairs of filaments are spaced from each other a given distance in a second direction. The monofilaments of each pair of filaments are revolved, at the moment of their extrusion and before being solidified, about an axis extending between the filaments of each pair of filaments so as to twist the filaments of each pair together and to thus integrally connect the filaments. One of the filaments of each pair of filaments is then moved in a second direction a distance equal to the spacing between pairs of filaments while continuing the extrusion of the filaments, after which pairs of filaments are again revolved as heretofore described. By continuously repeating the above steps and setting of the extruded filaments of plastic material, a net-like structure is provided.

In my United States patent application entitled Method for Continuously Extruding Net-Like Structures, Ser. No. 825,210, filed May 16, 1969, now U.S. Pat. 3,627,- 863, there is disclosed a method of making net-like structures of woven or braided monolaments using an apparatus similar to that described' in U.S. Patent No. 3,331,903.

Using conventional knitting, weaving or knotting processes, the strength and fiexibility characteristics of netlike structures can be brought into a desired balance using preformed twisted multifilament yarn. On the other hand, extruded net-like structures formed of monofilaments, as produced by methods disclosed in U.S. Pat. No. 3,33l,903 and my above-noted U.S. Pat. 3,627,863, as well as other methods known in the art, generally exhibit either good strength and poor fiexibility or poor strength and good flexibility. Accordingly, a primary object of this invention is the provision of an improved and more satisfactory method for making net-like structures.

Another object of this invention is to provide a method for making net-like structures which possess good strength and fiexibility characteristics.

Still another object is the provision of a method for making, net-like structures having twisted multifilament yarns which are interlaced with each other and/or twisted together at their crossing points.

These and other objects are accomplished in accordance with the present invention by a method in which a plurality of separate groups of closely spaced filaments are twisted into yarns which are then interlaced and/or twisted with each other. The filaments employed may be preformed or, as hereafter described, may be formed continuously and concomitantly with their manipulation into a net-like structure.

In the preferred practice, a plurality of separate groups of closely spaced streams of fiowable strand-forming materia] are continuously extruded, with the groups arranged in pairs. The groups of streams of each such pair of groups are spaced from each other in a first direction and the pairs of groups of streams are spaced from each other a given distance in a second direction. At least the surfaces of the extruded streams are set to provide groups of filaments, after which the filaments of each individual group are twisted to provide yarns. The groups of streams of each such pair of groups are revolved about an axis extending between the groups of each respective pair of groups to at least exchange the positions thereof. Relative movement is then imparted to the groups of streams in each such pair of groups in the second direction to arrange at least certain of the groups of each such pair of groups into different pairs. By continuously repeating the above sequence of movements concomitantly with the continuous extrusion of the groups of streams of strandforming material, setting of such streams into groups of filaments and twisting of the individual groups of filaments into yarns, a net-like structure of interlaced or twisted yarns is provided.

Preferably, the streams in each group of streams are alike in number, size and spacing, the groups of streams in each of the pairs of such groups are spaced like distances in the first direction and the pairs of groups are spaced like distances in the second direction.

During the revolving of the groups of streams of each such pair of groups, they are moved through an angle equal to a multiple of More specifically, the groups of streams of each such pair of groups may be revolved through an angle of only 180, providing that the direction of relative movement of the groups of streams in the second direction and the direction of revolution of the groups of each pair of groups is each reversed after the respective alternate movement has been completed. That is, relative movement of the groups of streams in each pair of such groups in a second direction is effected alternately with revolving of the groups of each pair of groups. Thus, if the direction of relative movement of the groups is reversed after each revolution of the groups of each such pair of groups, and the direction of revolution of the groups of each pair of groups is reversed after each relative movement of the groups, then each revolution of the groups may be limited to only 180. With this procedure the twisted multifilament yarns are interlaced with each other so that the resulting net-like structure is of woven or braided construction.

Revolving the groups of streams of each such pair of groups through an angle of 360 or further multiple of 180 will cause the individual twisted multifilament yarns formed from the respective groups of streams to be twisted with each other at their points or locations of crossing. The resulting net-like structure will exhibit good strength, yet will be flexible in view of the absence of bonding between the filaments in the individual yarns and between the yarns which are twisted to each other.

Obviously, the groups of streams of each such pair of groups may be revolved only 180 in certain instances and 360 or further multiples of 180 in other instances so that the resulting net-like structure will exhibit interlaced and twisted junctions between the multiiilament yarns.

If it is intended to revolve the groups of streams of each such pair of groups through an angle of 360 or further multiple of 360, the pairs of groups of streams, and the filaments and yarns formed therefrom, may be arranged in a circular array.

Relatively moving the groups of streams of each such pair of groups in the second direction may be achieved by moving only one group of streams of each pair of groups or by moving both groups of each pair of groups oppositely of each other or in the same direction but at different rates of speed. Further, when in a circular array, the groups of streams of each such pair of groups may be moved relative to each other by oscillating or rotating the one or both of such groups about an axis common to all the pairs of groups.

The apparatus employed in the method of the present invention includes cylindrical extrusion nozzles which are arranged as a plurality of spaced pairs to wh@ ilowable strand-forming material is continuously deliveredunder pressure. Each of the nozzles has a multiplicity of extrusion orifices whereby the liowable strand-forming material delivered to each nozzle is extruded therefrom as a group of separate streams. The extruded streams of each individual group are rapidly set into filaments and the nozzles are continuously rotated to twist each group of filaments into a yarn.

Periodically, each pair of nozzles is revolved through an angle equal to a multiple of 180 about an axis located between the respective nozzles of each such pair of nozzles whereby the groups of streams issuing from such pair of nozzles at least exchange positions. Operative alternately with the nozzle revolving means are means for relatively moving nozzles of each pair of nozzles into positions as to be arranged in different pairs.

The revolving means of the apparatus includes a plurality of semi-circular tables, with each having an opening within which is rotatably mounted an individual nozzle. The apparatus may be equipped to revolve the tables which support each pair of nozzles through an angle of only 180, with the direction of revolution of such tables being reversed after each relative movement of the nozzles of such pairs of nozzles and the direction of relative movement of the nozzles also being reversed after each revolution of the nozzles of each such pair of nozzles. The pairs of nozzles may be arranged in a circular array in which instance the apparatus would be adapted to revolve each pair of nozzles through 360 or further multiple of 360.

As in conventional extrusion apparatus for making netlike structures, suitable means, such as nip rollers, are provided for continuously advancing the nished net-like structure away from the extrusion apparatus concomitantly with its production.

The teachings of the present invention are applicable for use with a variety of liber-forming materials, which are referred to by the terms plastic and strand-forming materials, including polyolelins, such as polyethylene, polypropylene, polybutylene, polystyrene, polystyreneacrylonitrile blends, acrylonitn'le butadiene-styrene blends, acrylonitrile-butadiene copolymers, polybutene, polyisobutyiene, polyisoprene, and isobutylene-isoprene copolymers; halogenated oleiins, such as polyuoroethylene, polychloroiluoroethylene, polychlorotluoropropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl chloride-acetate copolymer, polyvinyl chloride-polypropylene copolymer, polychloroprene, iuorinated ethylene-propylene copolymers, vinylidene uoride-chlorotriuoroethylene copolymers, and vinylidene iluoridehexauoropropylene copolymers', polyesters, such as polyethylene terephthalate and copolymers thereof and polycarbonate; polyamides, such as polyhexamethyl adipamide, polycaprolactam, polyhexamethylene sebacamide, poly-aminoundecanoic acid; polyvinyl acetates; chlorinated polyethers, such as, ethylacrylate-chloroethylene vinyl ether copolymer; acrylic resins, such as polyacrylonitrile, polyacrylates and methacrylates; natural rubbers; compounded silicones; polyurethanes; polyethers, such as polyformaldehyde, formaldehyde-ethylene oxide copolymers, and polytrioxane; polysulfur resins, such as polysulfones and polysuldes; water-soluble, alkali soluble, and organic solvent-soluble cellulose esters and ethers, such as cellulose nitrate, cellulose acetate, cellulose butyrate, cellulose propionate, ethyl cellulose, viscose or cellulose xanthate, cuproammonium cellulose, and carboxymethyl cellulose; glasses; metals, etc. Such materials may include various additives such as stabilizers, dyes, foaming agents, etc., if so desired.

For a greater understanding of this invention, reference is made to the following detailed description and drawing in which FIG. l is a vertical section taken longitudinally of the apparatus employed in the method of the present invention;

FIG. 2 is a horizontal section taken substantially along the line II-II of FIG. l;

FIG. 3 is a partial vertical section, on an enlarged scale, taken transversely through the apparatus substantially along the line III-III of FIG. 2;

FIG. 4 is a view of the bottom of the apparatus as viewed along the line IV-IV of FIG. 3;

FIG. 5 is a fragmentary section taken substantially along the line V-V of FIG. 3;

FIG. 6 is a section of a portion of the apparatus taken substantially along the line VI--VI of FIG. 3; and

FIG. 7 is a perspective view of one of the elements of the apparatus.

With reference to the drawing, the apparatus employed in the method of the present invention includes a pair of vertical support members and 17,

side walls

19 and 21, which terminate well above the lowermost ends of the

support members

15 and 17 and a top wall 23. Walls and 27 project from each of the opposing sides of the

walls

19 and 21 and together deine channels 29 within which are slidably received

elongated plates

31 and 33.

Openings

35 and 37 are provided in the

support members

15 and 17 for the passage of the

plates

31 and 33 therethrough. The

plates

31 and 33, together with the

support members

15 and 17, side walls :19 and 21 and top wall 23, dene a chamber 39.

Flowable strand-forming material is continuously delivered under pressure into the chamber 39 through a conduit 41 from a suitable source, not shown. Gaskets are provided in the area of the

openings

35 and 37 in the

support members

15 and 17 to prevent leakage of strandforming material during sliding movement of

plates

31 and 33. A tank 43 is provided for containing a suitable setting liquid 4'5 in the area below the

ates

31 and 33.

In the specific embodiment illustrated, the contacting opposing

longitudinal edges

47 and 49 of the

plates

31 and 33 lie in a common plane and are each formed with a series of like, equally spaced

semi-circular recesses

51 and 53, respectively. Tables 55 and 57, having portions which correspond in shape to

recesses

51 and 53, are positioned within respective of such recesses for movement relative thereto, as hereafter described. The tables 55 and '57 are of like construction and, as best shown in FIG. 7, each include a straight or flat surface or wall 59, a semicircular wall 61 and a top flange 63 which projects over.

and rests on the top surface of the respective plates 31 and `33. Gear teeth 65 are formed along the walls 61 of the respective tables Y55 and 57 at a location as to be exposed below the bottom surfaces of the

plates

31 and 33.

Each of the tables 5S and 57 is formed with a suitable opening 67 Within which is rotatably mounted a nozzle 69 having a ange 71 at one end and a plurality of openings 73 at its opposite end. The nozzle anges 71 are seated within recesses extending annularly about the openings 67 in the respective tables S5 and 57, as shown in FIG. 3. Each of the nozzles 169 is formed with teeth 75 along its outer periphery, by means of which the nozzles are continuously rotated as hereafter described in detail.

With the fiat surfaces 59 of the tables 55 and 57 aligned with each other and with the opposing

longitudinal edges

47 and 49 of the

plates

31 and 33, at least one of the

plates

31 and 33, and the tables 55 and 57 carried thereby, is moved or shifted longitudinally. Preferably, both of the

plates

31 and 33 are shifted longitudinally in opposite directions relative to each other. This relative longitudinal movement of the

plates

31 and 33 is effected through

pins

77 and 79 which project from the

respective plates

31 and 33 and ride along -

grooves

81 and 83 formed in opposing surfaces of

cams

85 and 87.

The

cams

85 and 87 are of like construction and are fixed, in 180 out-of-phase relationship, to a shaft 89 which is supported by bearings, such as shown at 91, and is intermittently driven by suitable means, not shown. As more fully described hereafter, the

plates

31 and 33 are preferably moved a distance substantially equal to one-half of the center-to-center spacing of the

respective recesses

51 and 53 so as to move the tables 55 and 57, which are carried by the

plates

31 and 33, into different positions of alignment with each other.

Alternately with the longitudinal sliding movement of the

plates

31 and 33, aligned tables 55 and 57 which are carried by such plates are together revolved as a unit through an angle of 180 or further multiple thereof so as to at least exchange the positions of such pair of aligned tables. If in the practice of the method the tables are revolved through an angle of only 180, each such revolving movement is in a direction opposite to the previous revolving movement thereof so as to provide for interlacing of yarns, as more fully described hereafter.

Revolving of the tables is effected by

gear racks

93 and 95, which mesh with the gear teeth 65 formed along the semi-circular walls 61 of such tables 55 and 57. The

racks

93 and 95 are themselves intermittently driven by

gears

97 and 99, respectively, which are fixed to

shafts

101 and 103. The

racks

93 and 95 are guided for straight line motion by channels 105 which are formed by rabbeting the projecting Walls 25, as shown in FIG. 3.

In the arrangement illustrated in the drawing, the

racks

93 and 95 are designed to revolve aligned tables 55 and 57 through an angle of only 180, alternately with the shifting of the

plates

31 and 33, and thus gear teeth are present only along selected lengths of the

racks

93 and 95 and are omitted from portions indicated at 107 and 109. To provide for movement of the

racks

93 and 95, a distance necessary for revolving aligned tables 55 and 57 through an angle of only 180, the

gears

97 and 99 may be in the form of segment gears which are intermittently driven by oscillating the

shafts

101 and 103 in opposite directions.

Fixed to and depending from each of the

plates

31 and 33 are a pair of angle members 111 each having a vertical ange 113 and a horizontal ange 115. As best seen in FIGS. and 6, the vertical flanges 113 of the angle members 111 are each formed with rigid support hangers 117 which extend through spaced elongated slots 119 in the walls and are secured by screws 121 to the

respective plates

31 and 33. By this arrangement, the angle members 111 will both travel with the

plates

31 and 33 during their reciprocating movements.

Elongated platforms 123 are dovetailed to the horizontal fianges 115 of the angle members 111 for sliding movement generally perpendicular to the common plane, as defined by the abutting longitudinal edges of the

plates

31 and 33. As shown in FIG. 4, each of the platforms 123 is formed with a series of arms 125 which project toward the above-mentioned common plane. A sprocket 127, carried by a shaft 129, is rotatably mounted to the free end of each of the arms 125. Laced about the sprockets 127 carried by the respective platforms 123 is an endless chain 131 which is adapted to engage with the teeth 75 projecting from the periphery of the nozzles 69. The endless 6 chains 131 are continuously driven through gears 133, each of which is fixed to one of the shafts 129 carried by each of the platforms 123. The gears 133 mesh with and are driven by gears 135 which are fixed to the output shafts of separate electric motors 137.

The motors 137 serve to advance adjacent reaches of the pair of endless chain 131 in opposite directions so that the nozzles 69 are continuously rotated in the same direction. To insure continuous engagement of the endless chains 131 with the nozzle teeth 75, notwithstanding the movement of the nozzles as their supporting tables 55 and 57 are revolved, the platforms 123 are resiliently urged toward such nozzles by a series of leaf springs 139 located between the respective platforms and the adjacent flanges 113 of the angle mmebers 111.

In the practice of the method of the present invention with the specific apparatus described above, flowable strand-forming material is delivered under pressure through the conduit 41 and into the chamber 39. With the elements `of the apparatus positioned as shown in FIG. 2, the fiowable strand-forming material issues from the orifices 73 of the nozzles 69 as a group of straight streams, which are rapidly set into filaments, as by the liquid 45.

The motors 137 are then placed and maintained in continuous operation to drive the endless chains 131. The adjacent reaches of the pair of endless chains 131 are driven in opposite directions and are maintained engaged with the teeth on the nozzle peripheries by the action exerted upon the platforms 123 by the leaf springs 139. Thus, the movement of the endless chains 131 serves to continuously rotate the nozzles 69 so that the group of streams issuing from the orifices of the respective nozzles 69, and preferably the filaments formed from such streams, are twisted into yarns.

The cams and 87 are now operated to shift the

plates

31 and 33 in opposite directions, preferably a distance equal to one-half of the center-to-center spacing of the plate recesses 51 and 53. During this movement, the angle members 111 travel with the

respective plates

31 and 33, as heretofore explained.

With different tables 55 and 57 now aligned with each other,

plates

31 and 33 are held stationary while the

racks

93 and 95 are shifted by the

gears

97 and 99 to revolve only aligned pairs of tables 55 and 57 through an angle of only The nozzles 69 which are mounted within and moved with such tables are continuously rotated by the endless chains 131 so that the twisted yarns formed from the streams of strand-forming material issuing therefrom are moved from one side of the common plane to the other thereof.

The

plates

31 and 33 are now shifted by the cams 85 87 to the same degree but in opposite directions to their prior movement to align different tables 55 and 57 with each other. Again with the

plates

31 and 33 held fixed, the

racks

93 and 95 are driven to revolve only aligned tables 55 and 57 through an angle of only 180. The direction of revolution of the tables 55 and 57, however, is in a direction opposite to that in which aligned tables were previously revolved. By continuously repeating the abovedescribed steps, a net-like structure results having twisted multifilament yarns which are interlaced with each other.

As heretofore mentioned, in lieu of revolving the aligned tables 55 and 57 through an angle of only 180, the tables may be turned through 360 or a further multiple of 180 to provide a net-like structure in which individual extruded twisted multifilament yarns are themselves twisted with other of such yarns at their crossing points. Moreover, if the movement of the tables 55 and 57 is limited to complete 360 turns, or further multiples thereof, the various elements of the apparatus may be arranged in a circular array to thereby produce tubular net-like structures in which the twisted yarns are twisted with other yarns at their points of crossing.

I claim:

1. A method of making net-like structures including the steps of sequentially extruding a plurality of separate groups of closely spaced streams of fiowable strandforming material with the groups arranged in pairs, the groups of streams of each such pair of groups being spaced from each other in a first direction, and the pairs of groups of streams being spaced from each other in a second direction, setting the extruded streams of strand-forming material to provide filaments, twisting the filaments of each individual group of filaments into a yarn, revolving the groups of filaments of each such pair of groups about an axis extending between the groups of each respective pair of groups through 180 or further multiple of 180, relatively moving the groups of filaments of each such pair of groups in the second direction to arrange at least certain of the groups of filaments of each such pair of groups into different pairs, and continuously repeating the above sequence of movement, with the relative movement of the groups of filaments in the second direction and the revolving movement of the groups of filaments of such pair of groups occurring in alternate relationship.

2. A method as defined in claim 1 wherein relative movement of the groups of filaments of each pair of groups is effected by moving such groups oppositely of each other in a second direction and wherein the groups of filaments of each pair of groups are revolved through an angle equal to only 180, with each movement of the groups of filaments in the second direction and each revolving movement of the groups of filaments of each pair of groups being reversed after the respective alternate movement is completed.

3. A method as defined in claim 1 wherein the groups of filaments of each such pair of groups are revolved through an angle equal to a multiple of 360 and the pairs of groups of filaments and yarns formed from such groups of filaments are arranged in a circular array.

4. A mold as defined in claim 1 wherein the groups of filaments of each of the pairs of such groups are spaced from each other like distances in the first direction and the pairs of groups of filaments are spaced from each other like distances in the second direction.

5. A method as defined in claim 1 wherein the groups of filaments of at least some of said pairs of groups are revolved through an angle of 180 during certain of the revolving movements thereof and through an angle equal to a further multiple of 180 during other of the revolving movements thereof, with each movement of the groups of filaments in the second direction and each revolving movement of the groups of filaments of each pair of groups being reversed for at least such groups undergoing consecutive 180 revolving movements.

References Cited UNITED STATES PATENTS 629,637 7/ 1899 Whittington 87-24 976,946 11/ 1910 Storey 87-24 1,975,212 10/ 1934 Kobayashi 87-24 2,608,124 8/1952 Jeckel 87-9 3,298,274 1/1967 Wood 87-24 3,360,410 12/1967 Romanin 156-181 3,426,804 2/1969 Bluck 87-34 3,579,729 5/1971 Fairbanks 18-12 N 3,591,892 7/1971 Faidbanks 18-12 N 3,591,894 7/1971 Fairbanks 18-12 N 3,601,850 8/-1971 Fainbanks 18-12 N 3,331,903 7/1967 Mine 264-103 3,518,720 7/ 1970 Fairbanks 264-103 JAY H. WOO, Primary Examiner U.S. Cl. X.R.

28-1; 87-12; 139-1; ll-DIG. 6; 264-167, DIG. 81